Quality of service (QoS) may refer to the overall performance of a network, particularly the performance seen by the users of the network. To quantitatively measure quality of service, several related aspects of network service are often considered, such as error rate, bit rate, throughput, transmission delay, availability, jitter, or the like. Quality of service is particularly important for the transport of traffic with special requirements. QoS can be improved with traffic shaping techniques, such as packet prioritization, traffic classification, queuing, or the like.